a. If a portion of the surface is absolutely flat, you have the first order—Flat Relief.
b. If every portion of the surface is rounded, but none undercut, you have Round Relief—essentially that of seals and coins.
c. If any part of the edges be undercut, but the general protection of solid form reduced, you have what I think you may conveniently call Foliate Relief,—the parts of the design overlapping each other, in places, like edges of leaves.
d. If the undercutting is bold and deep, and the projection of solid form unreduced, you have Full Relief.
Learn these four names at once by heart:—
Flat Relief.
Round Relief.
Foliate Relief.
Full Relief.
And whenever you look at any piece of sculpture, determine first to which of these classes it belongs; and then consider how the sculptor has treated it with reference to the necessary structure—that reference, remember, being partly to the mechanical conditions of the material, partly to the means of light and shade at his command.
Fig. 9.